1. Field of the Invention
The present invention relates to new polyesters of aliphatic acylsuccinic acids, to a process for their preparation by a free radical mechanism and to their use for the production of thermosetting plastic and coating compositions.
2. Description of the Prior Art
Acylsuccinic acid has a tendency towards decarboxylation, so that direct esterification to form polyesters is not possible.
It is known that maleic acid esters or fumaric acid esters can be reacted with aliphatic aldehydes in the presence of free radical initiators to form monomeric acylsuccinic acid esters JOC 17 (1952) 1009 et seq. Oligomerization occurs to a minor extent during the reaction. Therefore, it was expected that crosslinking would occur during the corresponding reaction of unsaturated polyesters.
It has now been found that acylsuccinic acid polyesters, which can be crosslinked with polyisocyanates to form crosslinked coatings, can be produced by the reaction of unsaturated polyesters with aliphatic aldehydes in the presence of free radical initiators.